胞嘧啶脱氨酶基因联合放射对食管癌细胞株的杀伤作用

目的：观察大肠杆菌胞嘧啶脱氨酶／5-氟胞嘧啶（CD／5-FC）自杀基因系统对食管癌细胞株（EC109细胞）的杀伤效应以及与放射联合应用时对食管癌肿瘤细胞协同杀伤效应。方法：采用PCR方法，从大肠杆菌基因组DNA中扩增出CD基因；构建重组真核载体pcDNA3．1-CD；用脂质体转染法转染食管癌ECl09细胞，观察CD／5-FC体系对EC109细胞的杀伤效应和杀伤时的旁观者效应以及对放射的增敏效应。结果：RTP—CR分析结果表明CD基因已转入ECl09细胞并开始转录。体外实验证实，5-FC对转CD基因后的食管癌细胞株有明显的细胞毒作用，CD／5-FC体系对肿瘤细胞对放射增敏效果明显，加5-FC及放射治疗组细胞存活曲线低于单纯加前药5-FC对照组或单纯放射对照组。结论：CD／5-FC体系对肿瘤细胞的自杀效应具有旁观者效应和放射增敏效果。

Cellular Experimental Study of Suicidal Genes Combination with Radiotherapy on Carcinoma of Esopharynx Cell Line

Objective:Non-cytotoxic pro-drugs could be transformed by suicidal genes to cytotoxic pro-drugs which could make cells death. Among the system of suicidal genes, Coli cytosine deaminase/5-fluorocytosine (CD/5-FC) was studied on the lethal effect to clone of esopharyngeal carcinoma (EPC) and on the co-lethal effect combing with radiotherapy.Methods:With PCR method, CD gene was amplicated from DNA of Coli genome, eucarytic carrier pcDNA3.1-CD is recombinated. EC109 cells of EPC were transfected with liposome. The lethal effect of CD/5-FC to EC109 and the by-stander effect and enhanced sensitivity for radiotherapy were studied carefully.Results:The result of RTP-CR showed that CD gene had transfered to EC109 cell and had transcribed. In the test in vitro, it has been testified that 5-FC had significant cytotoxic effect on the cell strain of EPC with CD gene. The killing effect and bystander effect and radiosensitization effect of CD/5-FC suicide gene system to esopageal carcinoma cells was obvious.Conclusion:It is significant that by-stander effect of CD/5-FC and the effect of enhanced sensitivity for radiotherapy.